The invention relates to improvements in mechanisms for discharging material from pressure vessels. More particularly, the invention relates to a cellular wheel sluice for discharging solid or liquid material from a pressure vessel while reducing the pressure within the sluice.
In the foregoing type of apparatus for discharging material from a pressure vessel, one form of mechanism utilizes a housing with cells which are rotationally movable about a vertical axis with the cells being partially open. Means are provided for admitting material from the pressure vessel into the cells and means are provided for discharging the material from the cells. In the form involved in the present invention, a plurality of open cells rotatable about a vertical axis are covered at the top by a top sealing plate and at the bottom by a bottom sealing plate. The top sealing plate has a material admission opening. The bottom sealing plate has a material discharge opening offset with respect to the admission opening.
Material sluices for the transfer of solids and liquid material from a pressure vessel are conventionally known as cellular wheel sluices having a vertical axis. Such general arrangement is shown, for example, in German Published Application 33 35 860 which discloses such a sluice.
The cellular wheel housing glides between two sealing plates and an opening through which the material enters the cell from the pressure vessel is located in the top sealing plate. When the cell housing turns, the pressure is relieved in the cell and the material passes to the outside through an opening in the lower plate which is offset from the admission opening in the upper plate.
In this apparatus because the equipment is dealing with pressures and is in an environment of room pressure, the mechanism requires relatively expensive equipment with a technological outlay because of the wear that occurs. There is an air gap between the rotating cellular wheel housing and the top and bottom sealing plates because of occurring wear which proceeds with use. Material is expressed toward the outside through the air gap with a high flow rate if wear causes a gap. This is a consequence of the high pressure prevailing in the cellular wheel housing versus the room pressure on the outside of the housing.
Additional wear is caused by the equipment handling abrasive materials. As a result of the tightness of the cellular wheel sluice, this tightness decreases to an extent in a short time so that the sealing effect of the pressure vessel is lost. Mechanical readjustment of the sealing plates and a reduction in the size of the air gap between the plates and cell housing has been one of the solutions such as suggested in German Published Application 33 35 860 and the air gap is thus prevented from becoming constantly larger due to wear.
It is accordingly an object of the present invention to provide a cellular wheel sluice which avoids the disadvantages of structures of the prior art and wherein a simplified structure is utilized to guarantee the retention of tightness of the cellular wheel housing and with constant use, minimizes wear. A further object of the invention is to provide an improved cellular wheel sluice with unique sealing arrangements which coact with apparatus which prevents wear so that wear is reduced and the retention and maintenance of a tight seal is assured.